The present invention relates to hydrosilation reactions (often spelled "hydrosilylation" in the literature). It is well established that the addition of Si--H bonds to C.dbd.C or C.tbd.C bonds is catalyzed by various transition metals, their complexes and salts. In most cases, Speier's chloroplatinic acid and Wilkinson's rhodium complexes are the most effective catalysts, compared to the carbonyls of iron, cobalt, chromium, manganese and rhodium, and the complexes of platinum, palladium, iridium, rhodium and copper. Using Speier's chloroplatinic acid as a catalyst, hydrosilation reactions proceed with a great degree of efficiency, giving high yields, at room temperature.
Because platinum and rhodium are very expensive, it would be desirable to catalyze hydrosilation reactions with the less expensive transition metal, nickel. However, even hydrosilation pioneers such as Speier have been unable to get nickel to work as a practical matter at approximately room temperature.
Raney nickel is an excellent hydrogenation catalyst. However, artisans have not heretofore been able to use nickel as a practical commercial hydrosilation catalyst.
Petrov et al., Izvest. Akad. Nauk S.S.S.R., Ser. Khim. 1956, 256; Chem. Abstr., 1956, 50, 13726d, reported as early as 1956 that Raney nickel catalyzed the addition of trichlorosilane to acrylonitrile at 160 degrees C. for four hours in a sealed tube, yielding 13% .beta.-cyanoethyltrichlorosilane. However at 150 degrees C., most hydrosilation reactions will proceed to 15% yield even without a catalyst.
In 1970, Kumada et al., Chem. Comm., 1970, 611, reported that some nickel chloride phosphine complexes catalyzed the addition of methyldichlorosilane to a variety of olefins at 120 degrees C. for 20 hours to give the hydrosilation product in 55 to 87% yield. As above, a reaction at such high temperatures for such a long period of time is commercially impractical and certainly fails to suggest the use of nickel as a substitute for Speier's chloroplatinic acid or Wilkinson's rhodium complexes which facilitate hydrosilation rapidly and at room temperature.
The inoperability of nickel as a room temperature catalyst for hydrosilation reactions has been a great frustration to hydrosilation chemists, with very significant economic consequences. Billions of dollars in hydrosilation products have been produced using the more expensive, but operable platinum and rhodium catalysts.